Slant 6 engine ignition timing stays retarded.

Dana67Dart said

5 deg Atdc is retarded, you want to have it 0 to 5 to 10 Btdc so it's advanced. If you are trying to set it per factory spec (67 dart 273 with CAP calls for 5 Atdc) it will probably run like a turd.

0 = 5 advanced over factory
5 = 10 advanced over factory

I typically run 0 to 5 advanced as the CAP dist has a very aggressive advance curve in the lower RPM and vacuum range.

It is about the same as the non CAP after about 1500 to 2000 rpm

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I did not explain this very well. Your first paragraph is exactly what I'm looking for. I want 3-5 degrees advanced(BTDC) to begin with. I may modify that later. Factory spec happens to be 0 degrees. The problem is I can't advance the timing past 5 degrees retarded(ATDC) even rotating the distributor as far as it will go. Oh, I can retard it to infinity if I want. That's the issue.
What does CAP mean? Clean air something? How do I know? It did come with OSAC, but I disconnected that.